This invention relates to a method and apparatus for processing sand that is collected after a main mold made of green sand (or a main mold) is obtained after casting.
Japanese Patent Laid-open Publication No. Hei. 10-249482 discloses a conventional method for processing collected salad wherein the main mold is separated into sand that has been exposed to a high temperature from molten metal and outer sand surrounding that sand, wherein the sands are collected, wherein water and a binder are added to the sand that has been exposed to a high temperature, and wherein then the sand is mixed with the outer sand, the mixture to be reused.
However, the conventional method for processing collected sand includes some disadvantages. For example, it is difficult to adjust the moisture content in the collected sand and to add a binder to it when it is reused as molding sand. Also, a defect can be caused in a mold when it is made by the main mold that is made by reusing the molding sand. Also, a large system is needed to separate affected and unaffected sand and to collect them through respective paths.
This invention has been conceived to overcome these disadvantages. The object of this invention is to provide a method and apparatus for processing collected sand. This method and apparatus allow the moisture content in collected sand to be easily adjusted and a binder to be easily added to the collected sand so as to renew it as molding sand. Also, no defect is caused in the mold even if it is made by the renewed molding sand, and the apparatus for collecting sand can be compact.
To achieve the objects stated above, a method is provided for processing sand that is collected, after casting, from a main mold of green sand. The method includes the steps for separating the main mold of green sand into a part that has been unaffected by the heat of molten metal and a part that has been affected by the heat of the molten metal, adjusting the moisture content in the part that has been unaffected by the heat of the molten metal to use that part as facing sand when a new main mold is made, and adding a binder to the part that has been affected by the heat of the molten metal and adjusting the moisture content in the part to use it as back sand when a new main mold is made.
Also, a method is provided for processing sand that is collected, after casting, from a main mold made of green sand. This method includes the steps of separating each main mold of green sand into a part that has been unaffected by the heat of the molten metal and a part that has been affected by the heat of the molten metal, separately collecting the part that has been unaffected by the heat of the molten metal and the part that has been affected by the heat of the molten metal adding a binder to the part that has been affected by the heat of the molten metal and adjusting the moisture content in that part, mixing at a predetermined ratio the part to which a binder is added and in which the moisture content is adjusted with the part that has been unaffected by the heat of the molten metal, and adjusting the moisture content in the mixed material to use it as molding sand.
Also, a method is provided for processing sand that is collected after casting from a main mold made of green sand. This method includes the steps of separating each main mold of green sand into a part that has been unaffected by the heat of molten metal and a part that has been affected by the heat of the molten metal, separately collecting the part that has been unaffected by heat of molten metal and the part that has been affected by the heat of the molten metal mixing at a predetermined ratio the two kinds of the collected sand, adding a binder to the mixed sand, and adjusting the moisture content in the mixed sand to use it as molding sand.
Also, a method is provided for processing green sand for a main mold that is obtained by separating and collecting a main mold of green sand after casting. This method includes the steps of separating each main mold of green sand into a part that has been unaffected by the heat of molten metal and a part that has been affected by the heat of the molten metal, separately storing in respective storing means the part that has been unaffected by the heat of molten metal and the part that has been affected by the heat of the molten metal, processing and collecting the sand that has been separated and stored in the respective storing means by transferring the sand through the same path at different times, and collecting them in respective storing means, mixing at a predetermined ratio the two kinds of collected sand, and adjusting the moisture content in the mixed sand to use it as molding sand.
This processing method includes the step for collecting the parts by transferring the parts through the same path at different times. Thus, this method allows the moisture content in the parts to be easily adjusted and allows the binder to easily be added to the parts. Also, no defect is caused in molds even if they are made by the renewed molding sand. A large system is unneeded.
Also, an apparatus is provided for processing sand that is separated and collected from a main mold made of green sand after casting. This apparatus comprises means for separating each main mold made of green sand into a part that has been unaffected by the heat of molten metal and a part that has been affected by the heat of the molten metal and storing the parts, and means for separately collecting the part that has been unaffected by the heat of molten metal and the part that has been affected by the heat of the molten metal, which parts are then separated and stored. This apparatus also comprises means for separately storing the part that has been unaffected by the heat of the molten metal and the part that has been affected by that heat, which parts are separately collected, clay- and moisture-content-adjusting means for adding a binder to the part that has been affected by the heat and adjusting the moisture content in the part, blending means for blending the part that has been unaffected by the heat of the molten metal and the part that has been affected by that heat at a predetermined ratio, and mixing means for adjusting the moisture content in the parts and mixing the parts.
This apparatus does not need a plurality of collecting means. Thus, this apparatus can be compact. Also, this apparatus allows the moisture content in the parts to be easily adjusted and allows the binder to be easily added to the parts. Also, no defect is caused in molds even if they are made by the renewed molding sand. A large system is unneeded.